# How to run `prep_refdrone_data.py`

This script prepares the **RefDrone test split** for public inference. It is
strictly **web-only**: every annotation and image is downloaded from a public
mirror on each run. The script never reads any pre-existing local copy of
RefDrone or VisDrone elsewhere on disk.

## Prerequisites

- Python 3.8 or later
- Internet access (for HuggingFace and the VisDrone image mirrors)
- About **1 GB** of free disk for the temporary archive plus the extracted images

## Web sources

| What | Source | Size |
| --- | --- | --- |
| Annotation JSON (`RefDrone_test_mdetr.json`) | `https://huggingface.co/datasets/sunzc-sunny/RefDrone/resolve/main/RefDrone_test_mdetr.json` | ~3.3 MB |
| Image archive (`VisDrone2019-DET-test-dev.zip`) — primary | `https://github.com/ultralytics/assets/releases/download/v0.0.0/VisDrone2019-DET-test-dev.zip` (Ultralytics GitHub Release) | ~297 MB |
| Image archive — fallback | Google Drive id `1PFdW_VFSCfZ_sTSZAGjQdifF_Xd5mf0V` via `gdown` (canonical link from `https://github.com/VisDrone/VisDrone-Dataset`) | ~297 MB |

The image archive is tried in the order listed. The script falls through to the
next mirror automatically if one fails (including the well-known Google Drive
"too many users" quota error).

## Step 1 — Navigate to the repo root

```bash
cd /path/to/iib
```

The script's repo root is the `iib/` directory. All commands below are run from
there.

## Step 2 — Install `gdown` (only required for the Google Drive fallback)

```bash
pip install gdown
```

If the primary HTTPS mirror works, `gdown` is not invoked. Installing it
up-front is still recommended so the fallback works on machines where the
primary mirror is unreachable.

## Step 3 — Run the script

```bash
python3 scripts/refdrone/prep_refdrone_data.py
```

Flags:

| Flag | Effect |
| --- | --- |
| `--force` | Re-download annotation and image archive even if outputs exist |
| `--keep-zip` | Keep the downloaded `VisDrone2019-DET-test-dev.zip` after extraction (default: deleted) |

## What the script does

1. Downloads `RefDrone_test_mdetr.json` from HuggingFace (~3.3 MB).
2. Parses the annotation and writes `refdrone_data.jsonl` (3,276 rows, one per
   referring expression — no GT bboxes are ever written to this file).
3. Downloads `VisDrone2019-DET-test-dev.zip` (~297 MB) from the first working
   mirror, validates size, validates SHA-256, extracts the 1,503 required
   images into `images/`, then deletes the zip (unless `--keep-zip`).
4. Writes a `data_summary.json` report under `reports/` recording which
   mirror was used.
5. Hard-validates final counts: exactly **3,276** JSONL rows and exactly
   **1,503** `.jpg` files. Any mismatch aborts with a non-zero exit code.

## Output structure

Outputs are written under the repo root at:

```
iib/LMUData/Spatial/2d_referring_expressions/refdrone/
├── refdrone_data.jsonl                       # 3,276 rows
├── annotations_raw/
│   └── RefDrone_test_mdetr.json              # ~3.3 MB
├── images/                                    # 1,503 .jpg files
└── reports/
    └── data_summary.json
```

## Step 4 — Verify success

```bash
ROOT=iib/LMUData/Spatial/2d_referring_expressions/refdrone

# Annotation row count — must be 3276
wc -l "$ROOT/refdrone_data.jsonl"

# Image count — must be 1503
find "$ROOT/images" -name '*.jpg' | wc -l

# Confirm files_missing is 0 in the summary report
python3 -c "import json; print(json.load(open('$ROOT/reports/data_summary.json'))['images']['files_missing'])"
```

A run is successful only when:

- `refdrone_data.jsonl` has **exactly 3,276 lines**, and
- `images/` contains **exactly 1,503 `.jpg` files**, and
- The script ended with `Preparation complete (web-only download verified).`

The script enforces these checks itself in step 5 of its own flow and exits
non-zero on any deviation.

## Re-running

```
python3 scripts/refdrone/prep_refdrone_data.py            # normal run; reuses prior outputs from this script
python3 scripts/refdrone/prep_refdrone_data.py --force    # ignore prior outputs, re-download from scratch
python3 scripts/refdrone/prep_refdrone_data.py --keep-zip # keep the 297 MB zip after extraction
```

A re-run after a partial failure is safe: if a previous run already extracted
all 1,503 images into `images/`, the script logs that fact explicitly and
skips re-downloading. This is the only on-disk reuse the script performs;
external local copies of VisDrone or RefDrone elsewhere on the machine are
never consulted.

## Troubleshooting

### Primary HTTPS mirror unreachable

```
[images] Mirror FAILED: ultralytics-github-release — <error>
[images] Trying mirror: google-drive-original (gdrive)
```

The script automatically advances to the Google Drive fallback. No action
needed unless both mirrors fail.

### Google Drive quota error

```
[images] Mirror FAILED: google-drive-original — Google Drive refused the
request (likely quota / 'too many users' throttling): ...
```

If this is the *only* failure (primary mirror succeeded), the run already
finished correctly. If both mirrors failed, the script aborts with `ERROR: All
image-zip mirrors failed.` Wait an hour and retry, or download the zip in a
browser from
`https://github.com/ultralytics/assets/releases/download/v0.0.0/VisDrone2019-DET-test-dev.zip`
and re-run; the script will resume.

### Behind a firewall that blocks GitHub release assets

Allowlist `release-assets.githubusercontent.com` (Microsoft Azure Blob backend
for GitHub Releases). With that domain blocked, the primary mirror cannot
download even the redirected URL.

### `gdown` not installed

```
ERROR: gdown is required ... Install it with: pip install gdown
```

Run `pip install gdown`. The fallback Google Drive mirror needs it; the
primary HTTPS mirror does not.

### Checksum mismatch on the downloaded zip

```
ERROR: Checksum mismatch for VisDrone2019-DET-test-dev.zip
  The file has been deleted.  Re-run the script to download again.
```

The download was truncated or the upstream file changed. The corrupt zip is
already removed; just re-run the script. The script tries each mirror's own
SHA-256, so a successful download from any mirror is byte-verified.

### Final-validation failure

```
[validate] FAILED:
  - <one or more issues>
ERROR: Output validation failed.
```

The dataset is incomplete or corrupted. Run with `--force` to redo the
downloads from scratch.